Abstract Soil can form by bedrock weathering or by deposition of alluvial or aeolian material. To test the utility of detrital zircon U Pb geochronology for determining soil provenance, and to determine the provenance of soils in Middle Tennessee, samples of soil and underlying bedrock were collected from two sites, along with alluvium from a nearby river and loess from West Tennessee. Multi-dimensional scaling plots were used to compare complex detrital zircon LA-ICP-MS U Pb sample age distributions. Concentration ratios of immobile elements and Nd and Hf isotope compositions were also used as provenance indicators for comparison. At one site zircon U Pb ages and bulk sample trace element and isotopic compositions of soil were similar to the underlying limestone bedrock, indicating soil formation by bedrock weathering. In contrast, at a second site provenance tests indicate that soil from a late Pleistocene river terrace was sourced from alluvium rather than the underlying bedrock. Provenance inferences based on zircon U Pb ages were generally consistent with evidence from Zr/Hf ratios and Hf isotope compositions, which are all dominated by zircon, and Nd isotope compositions, which are not, although the best matches for different provenance indicators did not always agree. Zircon geochronology should be used with other soil provenance indicators to reduce effects of bias introduced by sedimentary sorting and sample processing.

中文翻译：

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评估锆石 U-Pb 年代学作为确定美国田纳西州中部石灰岩地体土壤来源的工具

摘要 土壤可以由基岩风化或冲积或风积物质的沉积形成。为了测试碎屑锆石 U Pb 年代学在确定土壤来源和确定中田纳西州土壤来源方面的实用性，从两个地点收集了土壤和下伏基岩样本，以及附近河流的冲积层和田纳西州西部的黄土. 多维标度图用于比较复杂碎屑锆石 LA-ICP-MS U Pb 样品的年龄分布。固定元素的浓度比和 Nd 和 Hf 同位素组成也被用作比较的来源指标。在一个地点，土壤的锆石 U Pb 年龄和大量样品微量元素和同位素组成与下面的石灰岩基岩相似，表明土壤是由基岩风化形成的。相比之下，在第二个地点的出处测试表明，来自晚更新世河流阶地的土壤来自冲积层，而不是下面的基岩。基于锆石 U Pb 年龄的物源推断与来自 Zr/Hf 比和 Hf 同位素组成的证据大体一致，这些证据均以锆石为主，而 Nd 同位素组成并非如此，尽管不同来源指标的最佳匹配并不总是同意。锆石年代学应与其他土壤来源指标一起使用，以减少沉积分选和样品处理引入的偏差影响。基于锆石 U Pb 年龄的物源推断与来自 Zr/Hf 比和 Hf 同位素组成的证据大体一致，这些证据均以锆石为主，而 Nd 同位素组成并非如此，尽管不同来源指标的最佳匹配并不总是同意。锆石年代学应与其他土壤来源指标一起使用，以减少沉积分选和样品处理引入的偏差影响。基于锆石 U Pb 年龄的物源推断与来自 Zr/Hf 比和 Hf 同位素组成的证据大体一致，这些证据均以锆石为主，而 Nd 同位素组成并非如此，尽管不同来源指标的最佳匹配并不总是同意。锆石年代学应与其他土壤来源指标一起使用，以减少沉积分选和样品处理引入的偏差影响。